Electromagnetic relay



l 1947- c. M. THEILLAUMAS ELECTROMAGNETIC RELAY Filed March E 24, 1943 BY. I

Patented July 1, 1947 UNITED STATES PATENT OFFICE ELECTROMAGNETIC RELAY Clement M. Theillaumas, Boulogne-Billancourt, France, assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application March 24, 1943, Serial No. 480,414 In France April 7, 1941 Claims. (Cl. 175-439) viding of polarized electromagnetic relays that i? are capable of a great diversity of combinations of interrupting or reversing contacts and that possess high sensitivity and speed of operation while requiring relatively little space and while being relatively inexpensive.

. According to certain details of this invention, the polarization of an electromagnetic relay armature is effected by modifying the magnetic circuit of the armature by means of a permanent magnet associated with this armature and disposed on the other side of the core with respect to the armature in such a way that the armature is or is not attracted, depending on the direction of the magnetization produced in the core by the exciting current of the relay.

Polarized electromagnetic relays that make use of features of this invention comprise, in association with each armature that is to operate for one direction only of the exciting current, a permanent magnet which, together with the armature, forms a fork or a bridge that frames the portion of the magnetic core which cooperates with that particular armature.

These features, as well as others, are explained For a relay of this type installed and adjusted in the usual way, the neutral position of the armature l is shown in Fig. 1 with the permanent magnet 3 adhering to the core 2 by magnetic attraction thereto.

If in the relay shown as being in the neutral position (Fig. 1), the winding [6 (Fig. 5) is fed with a current having such a direction that the core 2 becomes magnetized in such a way as to acquire in the portion facing the armature l a magnetization of the same polarity as that of the portion of the permanent magnet 3, the relay will operate because the permanent magnet 3 is then repelled by the core 2 of the same magnetic polarity, while the armature l is attracted by the core. Other things being equal, the rapidity of action due to attraction is greater than that of a relay of the same type which has no permanent magnet associated with its armature. As a matter of fact, as soon as the magnetization takes place at the free end of the core, the repelling force that acts on the magnet 3 is substantially the greatest possible, since the air gap between the magnet and the core is at a minimum in the neutral state of rest. The air gap between the core 2 and the armature I, which is at a maximum in the neutral condition, accordingly becomes reduced in size, whereas in the case of in detail in the following specification given with reference to the appended drawings which show only the portions of the relay that are necessary for an understanding of this invention:

Figs. 1 and 2 are schematic end views of a portion of a relay of fiat type that incorporates certain features of this invention;

Figs. 3 and 4 illustrate a modification of the design of Figs. 1 and 2;

Fig. 5 shows another type of construction embodying certain features of this invention as applied to the body of a relay.

Figs. 1 and 2, respectively, show the neutral and operated positions of a flat relay armature with respect to a stationary core 2. According to one embodiment of this invention, a. small permanent magnet 3 is added to the armature l. Together with the armature I, this magnet 3 as seen from the end or in vertical section has a Y-shapawhile the core 2 is located between the arms of this Y. The magnet 3 may extend parallel to the armature I, and be either as long as the armature or shorter, according to the degree of polarization required for the relay, and at the same time according to the material of which the magnet is made.

conventional relays the force of attraction is at a minimum because this air gap is at a maximum. As soon as the armature of a relay that incorporates certain principles of this invention has begun to move, the flux is unequally distributed between the two conjugated air gaps, these gaps being that between magnet and core and that between core and armature. The repelling effect keeps continuously decreasing but the attractive effect keeps increasing until the armature comes to adhere to the core, which latter position is shown in Fig. 2.

When the current of the exciting coil I6 is interrupted, the relay returns to rest or neutral position with a speed greater than that of a relay that has no permanent magnet, because the magnet attracts the core and does so with a force of attraction that becomes all the greater according as the air gap diminishes, and this effort accelerates the return of the armature into the position shown in Fig. 1 by supplementing the effect of whatever contact springs may be additionally employed for purposes of armature restoration.

If, when the illustrated relay is in the neutral position of rest (Fig. 1), the winding i6 is fed with a current having such a direction that the core 2 becomes magnetized in such a way as to acquire in the portion facing the armature l a magnetization of an opposite polarity to that of the free end of the permanent magnet, the relay 3 remains neutral or at rest owing to the mutual attraction of the magnet 3 and the core 2. The stability of the relay in its resting position even increases with the intensity of the exciter current but only to a certain extent because, when the the permanent magnet 3, the reversal of the direction of the current is without eiTect by itself and such current causes attraction of the armature, in whichever direction the current may how.

The permanent magnet 3 may be designed in various shapes depending on requirements, in practice. For example, as shown in Figs. 3 and 4, use may be made of a magnet 3 of bridge shape and having at the armature head i a profile that is symmetrical with respect to the plane of core 2. It is evident that in this latter case the arrangement should be such that the ends in contact with the armature arms shall have the same polarity. The other polarity is found at the center of the bridge-shape magnet 3' facing core '2. In brief, the device shown in Figs. 3 and 4 in the neutral and operated positions, respectively, is something like the on that would be formed by two similar magnets positioned back of each other with the like poles thereof placed in contact with each other.

The mode of polarization of a relay armature as just described only relates to the type of construction of the armature itself, and not to the body and the windings of the relay, nor even to other possibly employed armatures of this relay. Designs such as those above described consequently make it easy to manufacture polarized relays with multiple combinations of make and break, or reversing contacts. Furthermore, they are particularly applicable to flat types of relays, without substantially increasing the space occupied by such relays.

From the preceding descriptions it can be seen that relays including contacts designed like those above described have a high sensitivity and speed of operation. However, according to certain features of this invention, it is also possible to exert a predetermined influence on the sensitivity and speed of such relays, in this case by acting on the body proper of the relay. A schematic example of an embodiment of a relay modified accordingly is shown in Fig. 5.

In this Fig. 5, which shows a plan view of the magnetic circuit of a relay whose armature H is associated in the above described manner with a permanent magnet 13, the magnetic element or core consists of a sheet I 2, e. g., of soft iron, tightly joined over its entire length to a sheet l4 of a hypermagnetic alloy of suitable thickness. Any suitable form of energizing coil, such as IE5, may be employed to magnetize the core. The sheet l4 may, for example, consist of a sheet of a material such as those known under the trade names of permalloy, anhyster, etc,

For magnetizing fields of low values, almost all the magnetic flux (the distribution of which is shown in the drawing by the lines of force l5) passes through the sheet I4 which has less reluctance than the core 12. As a result of this, a relay which has its core made up in this way is made more sensitive and speedier if the sheet of hypermagnetic alloy [4 lies on the side facing the magnet [3, as shown in the drawings. It will, however, be less sensitive and not so speedy if this sheet I4 is installed on the side facing the armature I I.

It is evident that the invention is not limited to the examples of the types of construction described and shown herein, but that on the contrary it is capable of numerous modifications and adaptations to various types of fiat or other relays, without departing from the scope thereof.

What is claimed is:

1. Polarized relay device including a core, an energizing coil for magnetizing said core, an unmagnetized armature lying on one side of said core so as to be attracted thereby when said coil is excited, and a permanent magnet mechanically coupled to said armature so as to move and be moved simultaneously therewith and lying on the other side of said core from the side upon which said armature lies, whereby the polarity excited in said core by said energizing coil determines the respective attraction or repulsion of said magnet and thereby determines the position assumed by said armature in response to a predetermined direction of current in said energizing coil.

2. Polarized relay including a core, means for exciting said core, a composite fork-like armature structure embracing the active end of said core and havin one arm of the fork constituted by magnetic but unmagnetized material and the other arm of the fork constituted by permanently magnetized material, whereby the polarity excited in said active end of said core relative to said magnetized arm of said fork by a predetermined direction of current through said exciting means, determines the movement of said armature.

3. Polarized relay including an exciting coil, a core energized thereby and having an active :portion extending outside said coil, and a substantially symmetrical armature embracing said active core portion, said armature having the portion lying on one side of said core constituted by magnetic but unmagnetized material, while the portion of said armature lying on the other side of said core is constituted by a bridge-shaped permanent magnet having two like poles at the central portion of the bridge.

4. Device according to claim 2 and also including a sheet of hypermagnetic material located so as substantially completely to cover one side of said active end of said core.

5. Device according to claim 1 and also including a sheet of hypermagnetic material substantially completely covering the side of said core which faces said permanent magnet, whereby the sensitivity and speed of response of said relay device are enhanced.

CLEMENT M. THEILLAUMAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 819,322 Struble May 1, 1906 1,421,269 Lucas June 27, 1922 1,743,478 Pratt Jan. 14, 1930 1,770,673 Shaw July 15, 1930 2,203,888 Ashworth June 11, 1940 1,234,970 Todd July 31, 191'! 1,832,583 Roberts Nov. 17, 1931 

